A sexual act involving two guys and one girl the guys stand facing each other legs spread for balance and the girl is in between them. One guy penetrating the front the other in the butt; together the three make an image of the eiffel tower.

I totally double teamed this girl last night with Frank; we even got her into an Eiffel tower.

a sexual act that requires 3 people. 2 guys, one chick, and 1 other unfortunate soul. The chick bends over and one guy takes her from behind, while the other puts it in her mouth and then the two guys give a high ten, giving the illusion of the Eiffel Tower. The unfortunate soul is there to take the picture. No one will believe you if you don't have the proof.

Chad and Bob pulled off the Eiffel Tower with Beckie, while Trey, the unfortunate soul, took the picture.

latin: Concelebratio veneriis
In this group sex act, one man penetrates, or "doggies," a woman from behind while another gets a blowjob in front. During their exertions, the man--jubilant over their good fortune--reach up and high-five each other, thus forming an Eiffel Tower-like shape with their outstretched arms.
from the book: Dirty Sanchez's Guide to Buck Nasty Sex

I use Eiffel Tower on all my teams to build teamwork and camaraderie. If a couple of my players start fighting, I'll grab the waterboy and tell him to bend over and start sucking until my players learn to work together as a team. When that high-five happens, I know it's all coming together.

Okay, so two guys, they get this chick, right? And she's into them both, and that Lonely Island song and all that, so they form a human H with her and they're so proud of themselves that they just have to high five each other. But no, its a greater moment than that. They have to double high five!